1. Field of the Invention
The present invention relates to semiconductor device manufacture and, more particularly, to methods and structures for attaching semiconductor devices to lead frames.
2. State of the Art
During the manufacture of semiconductor devices, a semiconductor device or chip is often attached to a support, such as a lead frame. In general, a "leads-over-die" or "lead-on-chip" semiconductor device assembly has a lead frame with lead fingers that extend over the active surface of the semiconductor device supporting the semiconductor device being electrically connected to the bond pads located thereon, typically by wire bonds extending between the bond pads and the ends of the lead fingers, the other ends of the lead fingers for attachment to other circuit components. The lead fingers extend inwardly on the lead frame to bond pads located on the active surface of the semiconductor device for connection thereto as described in U.S. Pat. No. 4,862,245 (Pashby, et al.) and U.S. Pat. No. 5,304,842 (Farnworth, et al.).
The semiconductor device may be attached to the lead frame using adhesively coated tape as described in U.S. Pat. No. 5,304,842 (Farnworth et al.) or by the use of hot or cold adhesives as described in U.S. Pat. No. 5,286,679 (Farnworth et al.).
Use of hot or cold thermosetting or thermoplastic adhesives that have heretofore been suggested affect the processing of the semiconductor device assemblies as they require cure time for the adhesive and, in turn, cause delays in the manufacturing process to effect curing.
Therefore, it is desirable to have an adhesive for attaching the semiconductor device to a lead frame which has the shortest desirable cure time for the adhesive to allow the manufacturing process to proceed.